Electric starter motors

ABSTRACT

An electric starter motor for an internal combustion engine includes a casing, and a rotor shaft journaled for rotation in the casing. A pinion assembly is mounted on the rotor shaft for rotation with the rotor shaft, and is also capable of axial movement relative to the rotor shaft. A lever is coupled at one end to the pinion assembly, and is pivotally mounted intermediate its ends on the casing. Solenoid means is coupled to the end of the lever remote from the pinion assembly, so that operation of the solenoid means causes pivotal movement of the lever and therefore moves the pinion assembly axially relative to the rotor shaft. The lever is coupled to the pinion assembly through a plate which is pivotally connected to said one end of the lever. The plate is pivotable relative to the lever about an axis extending generally at right angles to the axis of rotation of the pinion assembly, and the pinion assembly is engaged with said plate so as to be rotatable relative thereto. Said plate is capable of movement relative to the pinion assembly in a plane generally at right angles to the axis of rotation of the pinion assembly.

United States Patent Roy Price Bowcott [72] Inventor Solihull, England [2!] Appl. No. 860,871 [22] Filed Sept. 25, 1969 [45] Patented Sept. 7, I971 [73] Assignee Joseph Lucas (Industries) Limited Birmingham, England [32] Priority Oct. 4, 1968 [3 3 Great Britain [3| 47191/68 [541 ELECTRIC STARTER MOTORS 3 Claims, 3 Drawing Figs.

[52] 0.8. CI 290/38 A [51] lnt.Cl F02n 11/02 [50] Field olSearch 290/38,48

[56] References Cited FOREIGN PATENTS l 361,073 4/1964 France 290/38 Primary ExaminerOris L. Rader Assistant Examiner-W. E. Duncanson, Jr. Attorney-Holman & Stern ABSTRACT: An electric starter motor for an internal combustion engine includes a casing, and a rotor shaft joumaled for rotation in the casing. A pinion assembly is mounted on the rotor shaft for rotation with the rotor shaft, and is also capable of axial movement relative to the rotor shaft. A lever is coupled at one end to the pinion assembly, and is pivotally mounted intermediate its ends on the casing. Solenoid means is coupled to the end of the lever remote from the pinion assembly, so that operation of the solenoid means causes pivotal movement of the lever and therefore moves the pinion assembly axially relative to the rotor shaft The lever is coupled to the pinion assembly through a plate which is pivotally connected to said one end of the lever. The plate is pivotable relative to the lever about an axis extending generally at right angles to the axis of rotation of the pinion assembly, and the pinion assembly is engaged with said plate so as to be rotatable relative thereto. Said plate is capable of movement relative to the pinion assembly in a plane generally at right angles to the axis of rotation of the pinion assembly.

PATENTEDSEP nan 3,603.803

SHEET 2 OF 2 mv NTE 91 BT m AT OQNEYS ELECTRIC STARTER MOTORS This invention relates to electric starter motors, for internal combustion engines, of the kind including, a casing, a rotor shaft journaled for rotation in the casing, a pinion assembly on said rotorshaft, said pinion assembly being rotatable with the rotor shaft and being movable axially relative thereto, a lever coupled at one end to said pinion assembly and pivotally connected intermediate its ends to the casing, and means operable to cause pivotal movement of the lever and thereby move the pinion assembly axially.

According to the invention, in a starter motor of the kind specified said lever is coupled to said pinion assembly through a plate which is pivotally connected to said one end of said lever for pivotal movement about an axis extending generally at right angles to the axis of rotation of the pinion assembly, said pinionassembly being engaged with said plate for rotation relative thereto, and said plate being capable of movement relative to said pinion assembly in a plane generally at right angles to the axis of rotation of the pinion assembly.

One example of the invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a fragmentary sectional view of a starter motor,

FIG. 2 is a plan view of the lever assembly of the motor shown in FIG. 1, and

FIG. 3 is an enlarged view of part of FIG. 1.

Referring to the drawings, the starter motor includes a casing 11 having joumaled for rotation therein a rotor shaft 12. The rotor shaft 12 carriesthe rotor of the starter motor, the

' rotor being surrounded by a stator assembly secured to the casing. Adjacent one end of the rotor shaft 12 is formed with a quickpitch, or equivalent, thread 13, with which is engaged a hollow sleeve 14. The sleeve 14 carries a thread complementary to the thread 13, and extends coaxially with the shaft 12. At its end remote from the rotor of the starter motor, the sleeve 14 is shaped to define the driving part of a conventional roller clutch, and cooperating with the driving part of the roller clutch is a pinion gear wheel 15 rotatably mounted on the shaft 12, and being shaped at one end to define the driven member of the roller clutch. Adjacent the pinion 15, the easing 11 is formed with an aperture 16 into which a toothed wheel (not shown) mounted on the crank shaft of the internal combustion engine, extends.

Mounted on the outer surface of the sleeve 14 for both axial and angular movement relative thereto is a collar 17. The collar 17 is retained on the sleeve 14 at one end by the roller clutch, and at the other end'by a circlip l8 and a washer 19. The collar 17 is urged towardsthe circlip 18 by a strong compression spring 21 which acts between the collar 17 and the body of the roller clutch. Positioned adjacent the stator of the starter motor, and mounted in the casing of the motor is a solenoid having a plunger 22which is urged outwardly by a compression spring 23. Projecting from the outer end of the plunger 22 is a plate, 24 which is formed with a slot 25 within which is received one end of a lever 26. The lever 26 is pivotally mounted at 27 on the casing 11, and extends towards the shaft 12. Said one end of the lever 26 is urged into engagement with the outer end of the slot 25 by means of a compression spring 28. The end of the lever 26 remote from the plunger 22 is bifurcated, to define a pair of limbs 29, 31 which extend on opposite sides of the shaft 11.

An annular plate 32 is trapped between the washer 19 and an outwardly directed periphery extending flange 17a on the collar 17. The plate 32 is formed with a pair of diametrically opposite parallel lugs 33, 34 which extend at right angles to the plane of the plate 32 and the lugs 33, 34 are pivotally connected by means of rivets 35 to the limbs 29, 31 respectively of the lever 26. The central hole 36 in the plate 32 is elongated in a direction at 90 to the pivotal axis of the plate, so that the width of the hole 36, measured in the direction of the pivotal axis of the plate 32, is smaller than the width of the hole 36 measured in a direction at ri ht an les to the pivotal axis of the The solenoid includes a switch which controls energization of the windings of the starter motor, and which is operatedby the plunger 22, so that when the solenoid is energized the plunger 22 is moved against the action of the-spring 23 and at some point during its movement closes'said switch toenergize the starter motor.

The operation of the motor is as follows. When the motor and the solenoid are deenergized, the parts of the starter motor are in the position shown in FIG. 1, the pinion 15 being disengaged from the toothed wheel of the engine with which the starter motor is associated. In order to start the engine, the solenoid is energized, so that the plunger 22 is withdrawn against the action of the spring 23. Movement of the solenoid 22 is transmitted by the plate 24 to the lever 26, and so the lever 26 is pivoted about the point 27. Thus, the assembly defined by the sleeve 14, the roller clutch and the pinion 15 is urged to move axially relative to the shaft 12 in a direction to engage the pinion 15 with the toothed wheel of the engine. By virtue of the thread 13, in order for the sleeve 14 to move axially on the shaft 12, the sleeve 14 must-rotate. Thus, as the pinion 15 is moved towards the toothed wheel of the engine it is also rotated. The spring 21 is so chosen that the force required to compress the spring 21 is greater than the force required to move the sleeve 14 axially, and so the spring 21 acts at this time as a solid sleeve, and the collar 17 and the plate 32 are thereby held against axial movement relative to the sleeve 14. When the plunger 22 of the solenoid has moved inwardly through sufficicnt distance to move the pinion 15 into partial engagement with the toothed wheel of the engine, said switch is closed and the motor is energized. At this stage there is resistance to rotation of the pinion since the pinion is engaged with the toothed wheel of the engine, and so initial rotation of the shaft 12, by virtue of the quick pitch thread 13, moves the pinion 15 into complete engagement with the toothed wheel. When the pinion 15 is in complete engagement with the toothed wheel of the engine, the sleeve 14 has reached the limit of its axial movement relative to the shaft 12, and so is locked against further movement in the same direction relative to the shaft 12. Thus, the pinion 15 rotates with the shaft 12 and drives the toothed wheel of the engine to crank the engine.

During the movement of the pinion 15 towards the toothed wheel, should the pinion l5 engage in tooth-to-tooth engagement with the toothed wheel of the engine, then the pinion 15 and consequently the sleeve 14 will be held against further axial movement relative to the shaft 12. However, the plunger 22 is still being withdrawn, and the corresponding movement of the lever 26 is taken up by compression of the spring 21. Thus when the switch controlling energization of the starter motor is closed by the plunger 22, the pinion 15 will be rotated relative to the toothed wheel of the engine thereby disturbing the tooth-totooth relationship, so that the pinion can move into engagement with the toothed wheel of the engine. When the tooth-to-tooth engagement between the pinion and the toothed wheel by the broken, the pinion is moved into mesh with the toothed wheel by the combined action of the spring 21 and the quick pitch thread 13. Should the engine start while the pinion is still in mesh with the toothed wheel of the engine, the starter motor will not be driven by the engine, since the roller clutch operates to permit the pinion 15 to rotate relative to the sleeve 14. When the solenoid is deenergized, the plunger 22 is urged outwardly by the spring 23 and the lever 26 is moved in a direction to withdraw the pinion 15 from the toothed wheel of the engine. Moreover, the inertia of the sleeve 14 and the roller clutch, as the shaft 12 slows down serves, by virtue of the thread 13, to move the sleeve 14, the roller clutch, and the pinion 15 back towards its original position.

It will be appreciated, that during pivotal movement of the lever 26, then the limbs 29, 31 and the plate 32 describe an arc of a circle having its center on the pivotal axis of the lever 26. Thus, the plate 32 is moved transversely relative to the sleeve 14 as the lever 26 is pivoted. The transverse movement of the tion of the hole 36 in the plate 32. Moreover, as the lever 26 pivots, the plate 32 pivots relative to the limbs 29, 31 of the lever about the rivets 35 to maintain the plane of the plate 32 at right angles to the axis of the sleeve 14.

Having thus described my invention what I claim as new and desire to secure by Letter Patent is:

1. An electric starter motor for an internal combustion engine, including, a casing, a rotor shaft, means mounting the rotor shaft for rotation in the casing, a pinion assembly carried by said rotor shaft, the pinion assembly being rotatable with the rotor shaft, and being movable axially relative to the rotor shaft, a lever coupled at one end to said pinion assembly, and pivotally connected, intermediate its ends, to the casing, for pivotal movement relative to the casing about a fixed axis, and means operable to cause pivotal movement of the lever and thereby move the pinion assembly axially, the lever being coupled to the pinion assembly through a plate which is pivotally connected to said one end of said lever, for pivotal movement about an axis extending generally at right angles to the axis of rotation of the pinion assembly, said pinion assembly being engaged with said plate for rotation relative thereto, and said plate being capable of movement relative to said pinion assembly in a plane generally at right angles to the axis of rotation of the pinion assembly.

2, A starter motor as claimed in claim I wherein said plate is generally annular and said pinion assembly includes a sleeve which extends through the central hole in the plate, the central hole in the plate being elongated in a direction at right angles to the axis about which the plate can pivot relative to the lever to permit said movement of the plate relative to the pinion assembly in a direction at right angles to the axis of rotation of the pinion assembly.

3. A starter motor as claimed in claim 1 wherein said plate is capable of axial movement relative to the pinion assembly, the pinion assembly including a spring which resists such axial movement. 

1. An electric starter motor for an internal combustion engine, including, a casing, a rotor shaft, means mounting the rotor shaft for rotation in the casing, a pinion assembly carried by said rotor shaft, the pinion assembly being rotatable with the rotor shaft, and being movable axially relative to the rotor shaft, a lever coupled at one end to said pinion assembly, and pivotally connected, intermediate its ends, to the casing, for pivotal movement relative to the casing about a fixed axis, and means operable to cause pivotal movement of the lever and thereby move the pinion assembly axially, the lever being coupled to the pinion assembly through a plate which is pivotally connected to said one end of said lever, for pivotal movement about an axis extending generally at right angles to the axis of rotation of the pinion assembly, said pinion assembly being engaged with said plate for rotation relative thereto, and said plate being capable of movement relative to said pinion assembly in a plane generally at right angles to the axis of rotation of the pinion assembly.
 2. A starter motor as claimed in claim 1 wherein said plate is generally annular and said pinion assembly includes a sleeve which extends through the central hole in the plate, the central hole in the plate being elongated in a direction at right angles to the axis about which the plate can pivot relative to the lever to permit said movement of the plate relative to the pinion assembly in a direction at right angles to the axis of rotation of the pinion assembly.
 3. A starter motor as claimed in claim 1 wherein said plate is capable of axial movement relative to the pinion assembly, the pinion assembly including a spring which resists such axial movement. 